2,507 research outputs found
When a Ban Is Not a Ban: Institutional Work and the Russian Doping Scandal
There are fewer cases of such blatant acts to defy and subsequent heroic efforts to rearrange institutional norms than the Russian doping scandal. In adopting a neo-institutional perspective, the authors theorize the scandal as a case of attempted but failed institutional disruption. More specifically, the authors draw upon the institutional change literature and the institutional work perspective to explain the key events surrounding actors’ response to the scandal. The analysis utilized Gioia’s methodological approach to examine secondary empirical data. Findings reveal how stakeholders circumvented traditional governance structures in an attempt to disrupt institutional arrangements, but despite this, much of the preexisting institutional infrastructure has remained intact. The authors explain this outcome, in part, as a consequence of the counter-institutional work of key governing agencies and other actors to maintain the status quo within international sport
Rauschenbusch’s Regurgitations: Rob Bell’s Promotion of a Realized Eschatology and His Alignment with Walter Rauschenbusch and the Social Gospel Movement
Rob Bell, author of the book Velvet Elvis: Repainting the Christian Faith, is one of the lead voices in the new emergent conversation. In his book, Bell’s ideas suggest a postmodern worldview for the modern day American church. Through this presupposition, Bell aligns himself with many of the liberal writers of the early nineteen hundreds, such as Walter Rauschenbusch of the Social Gospel movement. This arrangement has led to Bell’s reworking of many core orthodox positions, but in particular, the doctrine of eschatology. He asserts a form of realized eschatology, similar to Rauschenbusch, which misrepresents the gospel, while elevating the authority of man’s reasoning at the expense of that of Scripture
Navigational strategy switching in ageing
With advancing age, many cognitive faculties deteriorate, and navigation abilities
may be among those most affected. The majority of previous work investigating
navigation impairments in ageing has focused on allocentric processing, attributing
deficits to hippocampal dysfunction. However, real-world navigation is dependent
upon numerous different strategies, as well as the ability to flexibly switch between
them. Outside the context of navigation, it has been demonstrated that strategy
switching, thought to be coordinated by regions of prefrontal cortex and the locus
coeruleus-noradrenergic system, is also susceptible to the effects of ageing. Deficits
in navigational strategy switching, and prefrontal or noradrenergic dysfunction, are
therefore also likely to contribute to age-related navigation impairments. The work
presented in this thesis aimed to explore age-related impairments in strategy
switching within the context of navigation, and the underlying neural mechanisms in
terms of a prefrontal-noradrenergic model of switching.
The studies presented in Chapter Three assessed the use of allocentric and egocentric
navigational strategies by young and older people. Older participants tended to use
an egocentric strategy where an allocentric strategy was required, possibly due to a
difficulty in switching to the appropriate allocentric strategy. In Chapter Four, I
provide an account of two studies directly assessing navigational strategy switching,
using two different tasks based in virtual reality. The first study utilised a virtual
adaptation of the plus maze task, involving switching between an allocentric place
strategy and an egocentric response strategy, and demonstrated that older participants
were specifically impaired at switching to the place strategy. The second study used a
more realistic task set in a virtual town environment, which involved switching from
an egocentric route-following strategy to an allocentric wayfinding strategy, and also
demonstrated an age-related deficit in switching to an allocentric strategy.
In Chapter Five, I begin to explore the mechanisms underlying impaired navigational
strategy switching in ageing. Firstly, I describe a further behavioural study that used
variants of the virtual plus maze and a navigational gambling task to demonstrate a contribution of impaired decision making to the deficit in switching to an allocentric
strategy. This indicates that the deficit can be attributed, at least in part, to prefrontal
dysfunction. A second study presented in the same chapter demonstrated that
practising orienteering does not protect against decline in navigational strategy
switching ability with ageing. Chapter Six provides an account of my direct
assessment of the neural bases of navigational strategy switching using functional
magnetic resonance imaging. In young subjects, I found some evidence in support of
the roles of prefrontal regions in navigational strategy switching. However, I was
unable to complete development of a task suitable for assessing age differences in
functional activation of brain regions involved in navigational strategy switching.
The final experimental study, included in Chapter Seven, assessed pupil size and
heart rate as physiological correlates of noradrenergic activity during performance of
the virtual plus maze. Both young and old participants demonstrated a noradrenergic
response to all strategy changes, suggesting that impairments are more likely
attributable to dysfunction of prefrontal cortex than of the locus coeruleus, although
some subtle effects suggested that noradrenergic dysfunction does have some effect
on navigational strategy switching deficits. In the same chapter, I report the results of
a meta-analysis of data from five of the preceding studies, suggesting that deficits in
both strategy switching and allocentric processing combine to produce a greater
impairment in switching to an allocentric strategy.
The main finding of this series of studies is that navigational strategy switching is
impaired in ageing, which may contribute to the more widely reported difficulties
that older people have with navigation. My work also provides evidence in support
of a prefrontal-noradrenergic model of navigational strategy switching, and suggests
that dysfunction of prefrontal cortex and, to a lesser extent, the locus coeruleus-noradrenergic
system is responsible for decline in navigational strategy switching
ability with ageing. In conclusion, this thesis draws attention to the important role of
deficient executive processing and dysfunction of extra-hippocampal brain regions in
age-related navigation impairments
Extreme star formation events in quasar hosts over
We explore the relationship between active galactic nuclei and star formation
in a sample of 513 optically luminous type 1 quasars up to redshifts of 4
hosting extremely high star formation rates (SFRs). The quasars are selected to
be individually detected by the \textit{Herschel} SPIRE instrument at 3 at 250 m, leading to typical SFRs of order of 1000
Myr. We find the average SFRs to increase by almost a factor
10 from to , mirroring the rise in the comoving SFR density
over the same epoch. However, we find that the SFRs remain approximately
constant with increasing accretion luminosity for accretion luminosities above
10 L. We also find that the SFRs do not correlate with black
hole mass. Both of these results are most plausibly explained by the existence
of a self-regulation process by the starburst at high SFRs, which controls SFRs
on time-scales comparable to or shorter than the AGN or starburst duty cycles.
We additionally find that SFRs do not depend on Eddington ratio at any
redshift, consistent with no relation between SFR and black hole growth rate
per unit black hole mass. Finally, we find that high-ionisation broad
absorption line (HiBAL) quasars have indistinguishable far-infrared properties
to those of classical quasars, consistent with HiBAL quasars being normal
quasars observed along a particular line of sight, with the outflows in HiBAL
quasars not having any measurable effect on the star formation in their hosts.Comment: 12 pages, 6 figure
Supporting Pregnant Persons: The Benefits of Opening a Birth Centre in London, Ontario (Dynamic Doulas of London)
Aging specifically impairs switching to an allocentric navigational strategy
Navigation abilities decline with age, partly due to deficits in numerous component processes. Impaired switching between these various processes (i.e., switching navigational strategies) is also likely to contribute to age-related navigational impairments. We tested young and old participants on a virtual plus maze task (VPM), expecting older participants to exhibit a specific strategy switching deficit, despite unimpaired learning of allocentric (place) and egocentric (response) strategies following reversals within each strategy. Our initial results suggested that older participants performed worse during place trial blocks but not response trial blocks, as well as in trial blocks following a strategy switch but not those following a reversal. However, we then separated trial blocks by both strategy and change type, revealing that these initial results were due to a more specific deficit in switching to the place strategy. Place reversals and switches to response, as well as response reversals, were unaffected. We argue that this specific "switch-to-place" deficit could account for apparent impairments in both navigational strategy switching and allocentric processing and contributes more generally to age-related decline in navigation.© 2012 Harris, Wiener and Wolbers
Ball pen probe in strongly magnetised RF plasmas
A study of ball pen probes (BPPs) in a rf strongly magnetised plasma is reported for the first time. These probes have been successfully used in fusion plasmas, with magnetic fields up to 2.5 T, to measure the plasma potential. In this paper experimental results of various ball pen designs (2 and 4 mm diameter with flat and conical collectors) are presented up to 0.5 T in a low pressure capacitively coupled rf plasma. A theory of the BPP is developed, showing that the increase of the collector potential and plateau region, with collector retraction, requires the electron current to decrease faster than the ion current. Experimentally, it is found that to develop effective electron screening the electron Larmor radius should be smaller than the tunnel internal diameter. Smaller tunnels improve screening due to the tunnel entrance wall sheaths. Inside the tunnel a plateau region forms at 81 mT reducing to a broad peak at higher field strengths. Ion shielding and surface losses (for small tunnel diameters) reduce the collector peak width and maximum potential with increasing magnetic field. Conical collectors were found to increase the length of the plateau region and broaden the peak. Particle in cell simulations were in good agreement with the experimental results. The electron shielding and plateau regions were reproduced but not the broad peak at higher field strengths. Good agreement between both 2 mm BPPs and an emissive probe was found only at 81 mT to within 3 V or 1.3 electron temperatures (T e). For all BPPs at higher field strengths (≥ 250 mT) the maximum collector potential underestimated the emissive probe by more than 2.7 T e (7 V). At these field strengths all BPPs agree with each other to within 1.5 T e (4.1 V). Possible reasons for these disagreements are discussed
Testing White’s Floristic Impoverishment Hypothesis in the Forest-Savanna Transition Zones of Africa
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